With increasing development of the science and technology, data interaction between a base station and user equipment is increasingly frequent, and accordingly, a requirement on data interaction quality greatly increases, and therefore requirements of the user equipment on an area covered by a signal sent by the base station and on signal transceiving quality are becoming increasingly high.
However, compared with ordinary UE, some UE (user equipment, terminal device) may locate in a coverage area in which a signal is worse, for example, machine-type communications terminals such as an electricity meter and a water meter that are placed in a building, a basement, or an iron box. Signals in these places are not very good, and may have an extra maximum signal loss of 20 dB. To compensate the foregoing signal loss, generally a manner in which a signal is repeatedly sent (that is, spectrum spreading) is used to enhance the signal.
Specifically, in the prior art, when UE needs to perform random access, the UE first selects a random access code, and then selects a PRACH (physical random access channel) based on a PRACH configuration in system information. Then, the UE sends, on the selected PRACH, the selected random access code, and starts to attempt to acquire a random access response sent by a base station after duration of three subframes, where the random access response is scheduled by scrambling a PDCCH with an RA-RNTI (random access radio network temporary identifier).
For UE whose coverage level is worse, a same preamble needs to be sent by using multiple consecutive PRACH resources, and in this case, the following problems may occur: Because the coverage level of the UE is worse, in a process in which a preamble signal is repeatedly sent, the base station may be incapable of completely detecting all the same preambles. As a result, the base station cannot accurately determine start and end positions in which the UE repeatedly sends the PRACH resources of the preamble, and therefore correct access cannot be implemented. In addition, because normal UE (that is, coverage enhancement is not required) may still select a same PRACH resource, in this case, a conflict may occur between an FAR (random access response) repeatedly sent by the base station and an RAR obtained by a request of the normal UE. Therefore, the normal UE cannot correctly access the base station.